Plug and receptacle for use in hazardous locations



Dec. 26,1967 c. H. RONGEY ET AL PLUG AND RECEPTACLE FOR USE IN HAZARDOUS LOCATIONS Filed May 26, 1965 CLARENCE H. Rowan; MARSHA L L 6. 2A VERTN 2 Sheets-Sheet l 7. H 5 5 m m Dec. 26, 1967 c. H. IIQONGEY ET AL 3,360,763-

PLUG AND RECEPTACLE FOR USE IN HAZARDOUS LOCATIONS Filed May 26, 1965 2 Sheets-Sheet 2 w v 5 /\/7'0 Q5! CLAQEA/CE H. RONGEY, MQRSHALL 5. 2A VER T/v/K,

United States Patent 3,360,763 PLUG AND RECEPTACLE FOR USE IN HAZARDOUS LUCATIONS Clarence H. Rongey, Granite City, Ill., and Marshall G.

Zavertnik, Manchester, Mo., assiguors to Killark Electric Manufacturing Company, St. Louis, Mo., a corporation of Missouri Filed May 26, 1965, Ser. No. 458,956 4 Claims. (Cl. 339-14) ABSTRACT OF THE DISCLOSURE A plug and receptacle for use in hazardous locations, the plug and receptacle each being formed with a cylindrical or sleeve body sized to be telescoped together. Releasable interlocking means hold the sleeves in telescoping relationship.

Summary of the invention In general, the invention comprises a plug and receptacle, each formed with a cylindrical or sleeve body. The sleeves are of diiferent diameters so that they can be telescoped together. Contact elements are supported within the sleeves by insulators and are disposed to make 1 contact when the two sleeves are pressed together in telescoped relationship. The contact elements are constructed so that they must be properly oriented before they can make contact with one another.

The sleeves are sufiiciently long so that they are in telescoped relationship prior to the establishment of electrical contact between the contact elements. There is a depressible interlock button carried by one of the sleeves that cooperates with a slot in the other sleeve to prevent complete separation of the sleeves until the interlock button is depressed. However, there is a lost motion relationship between a portion of the interlock button and the slot to enable the electrical contact between the contact elements to be broken before the sleeves are completely separated from one another. The interlock button is also constructed to prevent complete separation of the sleeves until the interlock button is depressed. Thus, the plug and receptacle are designed to break the electrical contact upon the occurrence of an internal explosion or sudden withdrawal of the plug, without exposing the contact elements to the explosive atmosphere outside the telescoped sleeves.

The general object of this invention is to provide a plug and receptacle for use in a hazardous location whereing the contact elements are arranged to permit a break in the electrical contact. The plug and receptacle are constructed to prevent arcing of the contact elements to the atmosphere surrounding them even upon breaking of the electrical contact.

Another object of the invention is to provide a plug and receptacle for use in hazardous locations wherein the plug and receptacle have cooperating housing parts to enclose contact elements and wherein there is an interlock between the plug and receptacle housings to permit them to slide relative to one another for breaking the electrical contact between their contact elements, while preventing complete separation of the housing elements until the interlock is positively operated.

Another object of the invention is to provide a plug and receptacle for use in a hazardous location, with an adapter to permit the receptacle to be used as a cord connector with conducting Wires connected to it or to the receptacle, wherein the adapter may be threaded into an opening in the wall of a device suitable for use in a hazardous location.

Another object of the invention is to provide a plug 3,36%,763 Patented Dec. 26, 1967 and receptacle for use in a hazardous location wherein the construction of parts is such that the replacement of complete contact assemblies consisting of insulators and contacts is expedient and can be done rapidly and economically.

Other objects and advantages will be apparent to those skilled in the art.

In the drawings:

FIGURE 1 is a side elevation view of the connector and receptacle assembled together with the adapter in place;

FIGURE 2 is a side elevation view of the receptacle of FIGURE 1 rotated FIGURE 3 is a left end view of the plug and receptacle of FIGURE 1 on a slightly enlarged scale;

FIGURE 4 is a right end view of the receptacle of FIGURE 1 on a slightly enlarged scale;

FIGURE 5 is a fragmentary side elevation of the receptacle of FIGURE 2, but with the plug and receptacle shown in the positions they would occupy when electrical contact is broken but the interlock button has not released the plug and receptacle;

FIGURE 6 is a view in section taken along the line 66 of FIGURE 3 and of FIGURE 4;

FIGURE 7 is a view in section taken along the line 7-7of FIGURE 1 and of FIGURE 3;

FIGURE 8 is a fragmentary View in section similar to -that of FIGURE 6, but showing the plug and receptacle in the positions they occupy upon breaking the electrical contact, such as upon the occurrence of an emergency, corresponding to the view of FIGURE 5;

FIGURE 9 is a fragmentary view in section similar to that of FIGURES 6 and 8, but showing the plug and receptacle completely separated;

FIGURE 10 is a fragmentary enlarged view in section showing the attachment of the insulator disk and the ground contact terminal within the plug sleeve;

FIGURE 11 is a side elevation view on a reduced scale of the receptacle sleeve with the interlock button removed;

FIGURE 12 is an end elevation view of the insulator block which is mounted within the receptacle sleeve;

FIGURE 13 is a top plan view of the insulator sleeve of FIGURE 12;

FIGURE 14 is a view in section taken along the line 1414 of FIGURE 12;

FIGURE 15 is a bottom plan view of the insulator sleeve of FIGURE 12;

FIGURE 16 is a top plan View of the interlock button;

FIGURE 17 is a side elevation view of the interlock button;

FIGURE 18 is a rear elevation View of the interlock button;

FIGURE 19 is an end elevation view of the insulator disk and contact terminals which are mounted within the plug sleeve; and

FIGURE 20 is a view in section taken along the line 20-20 of FIGURE 19.

This assembly 30 comprises a plug 31 and a receptacle 32. There is also an adapter 33 for converting the receptacle to a cord connector receptacle. The receptacle 32 is threaded to fit standard outlet hubs such as are used on devices which are suitable (designed) for use in said hazardous locations.

The plug 31 comprises a cylindrical aluminum shell 35 with a cylindrical inner wall 36 and ends 37 and 38. The end 38 of the shell 35 has a reduced portion with external threads 39 and an internal diverging wall 40.

A cap 42 is adapted to 'be threaded onto the end 38 of the shell 35. The cap 42 has an opening 43 through its end 44 with a beveled surface 45 inwardly of the opening 43. A gasket 46 is pressed against the tapered surface 40 other somewhat yieldable insulating material. It is made with various inside diameters to accommodate and grip diiferent sizes and types of cord or cable.

There is a rigid disk 50 of insulating material that fits within the space defined by the inner cylindrical wall 36. The disk 50 is of molded plastic construction and is molded about the rough kinurled portions 51 of two female power contacts 52.. Each female power contact 52 includes a cylindrical portion 53 of about 1% inch in length including the rough knurled portion 51 which is about A inch inlength. There is a contact recess 55 in the end of the cylindrical portion 53 of about inch in length. A crimptype solderless lug extension 56 of slightly smaller diameter extends from the knurled end of the cylindrical portion 53. The contacts 52 are molded integrally with the disk as an assembly.

The disk 50 also has a recess 58 in it with a hole 60 communicating with the recess 58. A female ground contact 61 has a cylindrical portion 62 seated within the recess 58 and a smaller diameter crimp-type solderless lug extension 63 extending through the hole 60. The cylindrical portion 62 is about 1% inchesin length, including a rough or coarse knurled portion 64 of about inch in length. The crimp-type solderless lug extension 63 is about inch in length. There is a contact recess 65 within the cylindrical portion 62 that is about 1% inch in length.

As best seen in FIGURE 10, there is a threaded hole 67 through the coarse knurled portion 64 and adapted to be aligned with a tapped hole or recess 68 in the disk 50. There is a counter-sunk hole 69 through the wall of the shell 35 for receiving the head of a set screw 70. The screw 70 threads into or through the disk 50 and into the ground contact 61 to hold .both in place within the shell 35.

A conductive ground contact clip 72 may be used if desired. The clip 72 has a sleeve 73 that fits over the crimptype lug extension 63 and an arm 74 that contacts the screw 70. The clip 72 thus assures electrical contact between the shell 35 and the female ground contact 61.

The receptacle 32 comprises an aluminum shell 80 having an annular stop flange 81 of slightly larger diameter surrounding it and defining a stop shoulder 82 on one side and a stop shoulder 83 on the other side. There is an extension 84 with external threads 85 and with an inwardly crimped end 86. An inner wall 87 is cylindrical and of constant diameter except for the reduced diameter portion defined by the inwardly extending annular flanged portion 86.

An insulator plug or disk 90 fits within the space defined by the inner wall 87. The insulator plug 90 is molded about two male power contacts 91 and a male ground contact 92. Each male power contact 91 has a knurled portion 93 forming part of a cylindrical portion 94 of about Ms inch in length, and has a smaller diameter contact prong portion 95 extending forwardly therefrom, of about 78 inch in length. There is a recess 96 in the plug 90 extending from the end of the plug and surrounding each prong 95. Each recess 96 is slightly larger in diameter than the diameter of the female power contact 52.

The ground contact 92 has a cylindrical portion 97 with a knurled portion 98 at its end and with a prong portion 99 extending beyond the cylindrical portion 97. The prong portion 99 is about 1% inch in length, and a recess 100 surrounds the prong 99 and is sized to receive the female ground contact 61. There are crimp-type solderless lug extensions 101 and 102 on the power contacts 91 and the ground contact 92, respectively.

The diameter of the prong 99 is greater than that of the prongs 95, and the contacts 99 and 95 cannot be inserted into therecesses of the cont-acts 52 and 61 unless the contact 99 is aligned with the recess 65 of the contact 61.

A ground clip 105 has a sleeve portion 106 surrounding the crimp-type lug extension 102, with a tab 107 extending into pressed engagement between the plug and the flange portion 86 of the sleeve 80. The clip thus establishes an electrical connection between the ground contact 92 and the shell 80.

There is a slot 110 in the shell 35. The slot 110- has a rounded end 111 and rounded corners 112 and 113 terminating in a narrower width passage 114 opening to the end 37 of the sleeve. The slot 110 and passage 114 are designed to cooperate with an interlock button 116 which is mounted on the receptacle 32.

The interlock button 116 is made of brass or other metal, and as illustrated particularly in FIGURES 16-18, has a knurled cross member 117 extending between spaced arms 118 and 119. The receptacle shell 80 has a pair of holes 120 and 121 through it, and the arm 118 has a portion 122 which is of a proper width to extend through the hole 120. The insulator plug 90 has a recess 123 opposite the holes 120 and 121 so the interlock button 116 can be operated.

A rearwardly extending tab 124 hooks under the shell 80 at the end of the hole 120. There are laterally extending wings 125 and 126 on opposite sides of the arm 118, spaced from the outer surface of the shell 80. The total width of the buuton at the wings 125 and 126 is greater than the width of the passage 114. However, the arms 118 and 119 are sufliciently narrow to pass through the passage 114.

The other arm 119 has a cylindrical base 127 the diameter of which is about equal to the width at the wings 125 and 126. The cylindrical base meets the narrower outer arm portion 128 in an inclined camming surface 129. The base 127 extends through the hole 121 in the shell 80 and has clip 130 pressed onto a hub 131 on the base to hold the button in place. A compression spring 132 bears against the wall of the recess 123 and against the base 127.

When the shell 35 is over the shell 80 with the end 37 stopped against the shoulder 82, the narrow portion 122 of the arm 118 of the interlock button 116 is positioned within the narrower width slot 114. In this position, the wings 125 and 126 of the button 116 extend beyond the edges of the slot 114, and the button 116 cannot be depressed. The length of the wings 125 and 126 is such that when the plug shell 35 is pulled from the receptacle shell 80 a short distance until the base 127 of the arm contacts the rounded corners 112 and 113 of the slot 110', the shoulders 125 and 126 are beyond the slot 114 and the interlock button 116 can be depressed.

The round base 127 of the arm 119 is of larger diameter than the width of the slot 114. The base portion 127 can slide in the slot 110 but will not fit through the slot 114. Upon depression of the interlock button 116 against the force of the compression spring 132, the base 127 is pressed inwardly of the shell 35 until its surface 129 is inward of the inner surface 36 of the shell 35. The arm portion 119 beyond the base 127 being sufliciently narrow to pass through the slot 114, the plug 31 can be separated from the receptacle 32.

The cord connector adapter 33 comprises a tube 135 which has a cylindrical side wall 136 one end of which is provided with internal threads 137, and the other end of which is provided with external threads 138. There is a tapered entrance 139' at the externally threaded end for receiving a rubber or other flexible material grommet 140 which is held in place by a cap 141. When the tube 135 is threaded onto the end 84 of the receptacle 32, the ends of the contacts 91 and 92 are contained within the tube 135. Connecting wires can be extended through the grommet 140 and attached to the lugs 101 and 102.

In use, the plug and receptacle described heretofore may be used as shown in FIGURES l and 2, or it may be used without the adapter 33. When the adapter 33 is removed, the threads 85 are exposed. These are standard A.S.A. threads and can be threaded into a tapped hole in the wall of a box or other enclosure to enable attachment of wires to the lugs 101 and 102.

If the plug and receptacle are to be used as a standard cord connector, the adapter 33 is put in position as shown in FIGURES 1 and 2, and wires are extended through the grommet 140 and are attached to the lugs 101 and 102 by use of a crimping tool. Wires are also extended through the grommet 4-6 and are attached to the lugs 56 and 6.3 by a crimping tool. If desired, the wires can be soldered instead of attached by crimping.

The electrical contact between the contacts 52 and 61 in the plug 31 and the contacts 91 and 92 in the receptacle 32 is made upon moving the shell 35 over the shell 80. As the shell 35 is started, the end 37 thereof contacts the camming surface 129 on the base 127 of the interlock button 116 and automatically depresses that button so that the base 127 does not contact the opposite walls of the entry passage 114.

As the shell 35 is slid along the shell 80, the base 127 reaches the wire slot 110 and snaps to the position shown in FIGURE 8 under the force of the compression spring 132. In this position, as FIGURE 8 shows, the ground prong 99 of the contact 93 has started within the recess 65 of the ground contact 61 to establish a ground contact, and this ground contact is transmitted through the ground clip 105 to the shell 80 and through the ground clip 72 to the shell 35. However, contact between the prong 95 and the contact 52 has still not taken place.

When the shell 35 is slid all the way onto the shell 80 so that the end 37 contacts the shoulder 82 on the shell 80, electrical contact is established between the prongs 95 and the recesses 55 of the contacts 52, as shown in FIGURES 6 and 7.

There is a friction fit between the inner wall 36 of the shell 35 and the outer surface of the shell 80, but these two shells can be slid relative to one another within the limits of the lost motion between the base 127 of the interlock button 116 and the slot 110. The base 127 can slide between the rounded end 111 and the rounded corners 112 and 113, as shown in FIGURES 2 and 5.

Should an explosion occur, tending to separate the shell 35 from the shell 80, or should there be any other emergency reason to break the contact between the current carrying contacts 91 and 52, the shells are slid to the relative positions illustrated in FIGURE 8. Again, the electrical contact between the contacts 95 and the recesses 55 in the contacts 52 is broken. However, the base 127 stops against the rounded corners 112 and 113 and prevents complete separation of the sleeves 35 and 80, and maintains ground connection between contacts 99 and 61. This prevents exposure of the area within these sleeves to the surrounding atmosphere where there may be explosive gases or the like.

To completely remove the shell 35 from the shell 80, the interlock button 116 must be depressed against the force of the compression spring 132 to move the base 127 inwardly of the shell 35. When this is done, the interlock button can slide through the entry passage 114 and the plug can be separated from the receptacle, as illustrated in FIGURE 9.

Various changes and modifications may be made within the purview of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended thereto.

What is claimed is:

1. A connector for hazardous locations comprising a plug and a receptacle formed of complementary telescoping sleeves, contact terminals including power and ground terminals supported by the plug and receptacle within the sleeves and adapted to make electrical contact when the sleeves are telescoped, releasable interlocking means to hold the sleeves in telescoping relationship, and means rendering the interlocking means yieldable to permit relative sliding of the sleeves to break electrical contact between the power terminals while preventing separation of the sleeves, the interlocking means comprising a slot in one of the sleeves, an entry to the slot from the end of the sleeve nearest the other sleeve, the entry being narrower than the slot, and a depressible button carried by the other sleeve, the button being slidable through the entry when depressed and being locked from sliding through the entry when not depressed, the contact terminals including a ground terminal in each sleeve, the ground terminals being longer than the other terminals and being sufliciently long to maintain electrical contact with one another when the sleeves are slid to their unseparated positions with the electrical contact between the hot terminals broken.

2. A connector for use in hazardous locations comprising a pair of sleeves, one sleeve being of larger diameter than the other sleeve to enable the sleeves to be tele' scoped together, contact sockets including a ground contact and at least one power contact supported in one sleeve and contact prongs including a ground prong and at least one power prong supported by the other sleeve and adapted to be inserted into the contact sockets to establish electrical contact therewith when the sleeves are telescoped together, the smaller diameter sleeve having means to support a depressible interlock button, the larger sleeve having an elongated slot for receiving the interlock button when the sleeves are telescoped together, a narrow entry passage leading to the slot, the interlock button having a portion which will slide in the slot but Which prevents passage of the interlock button through the entry passage unless the button is depressed, the slot and the last named portion of the button having a lost motion fit enabling the sleeves to be relatively slid within restricting limits without depression of the interlock button, (and electric contact elements carried by the sleeves and adapted to establish electrical contact with one another when the sleeves are telescoped together,) the interlock button having means to prevent its depression unless the sleeves are in such relative positions as to locate said button portion at the end of the slot adjacent the entry passage, the ground contact elements being of such a length that electrical contact between them is maintained whereas the power contact elements are of such lengths that electrical contact between them is broken when the sleeves are in the last named relative positions.

3. The connector of claim 2 wherein the contact eler'nents are fixed in molded insulator plugs supported within the sleeves, and one of the sleeves has a removable portion for enabling the receptacle to be connected into a wall opening.

4. The connector of claim 2 including means requiring proper orientation of contact elements before they can establish electrical contact with one another.

References Cited UNITED STATES PATENTS 1,829,207 1-0/ 1931 Adleman 339126 1,997,081 4/1935 Reynolds 33989 X 2,002,177 5/ 1935 Hastings 33989 2,281,654 5/1942 Wulle et al. 33989 2,410,618 11/1946 Zelov 339--14 2,502,303 3/ 1950 Arson et al. 33991 2,626,974 1/ 1953 Howard et al. 3399l 2,626,975 1/1953 Rockwell et al 339-91 2,662,219 12/ 1953 Hennessey et al. 339-90 MARVIN A. CHAMPION, Primary Examiner. 

1. A CONNECTOR FOR HAZARDOUS LOCATIONS COMPRISING A PLUG AND A RECEPTACLE FORMED OF COMPLEMENTARY TELESCOPING SLEEVES, CONTACT TERMINALS INCLUDING POWER AND GROUND TERMINALS SUPPORTED BY THE PLUG AND RECEPTACLE WITHIN THE SLEEVES AND ADAPTED TO MAKE ELECTRICAL CONTACT WHEN THE SLEEVES ARE TELESCOPED, RELEASABLE INTERLOCKING MEANS TO HOLD THE SLEEVES IN TELESCOPING RELATIONSHIP, AND MEANS RENDERING THE INTERLOCKING MEANS YIELDABLE TO PERMIT RELATIVE SLIDING OF THE SLEEVES TO BREAK ELECTRICAL CONTACT BETWEEN THE POWER TERMINALS WHILE PREVENTING SEPARATION OF THE SLEEVES, THE INTERLOCKING MEANS COMPRISING A SLOT IN ONE OF THE SLEEVES, AN ENTRY TO THE SLOT FROM THE END OF THE SLEEVE NEAREST THE OTHER SLEEVE, THE ENTRY BEING NARROWER THAN THE SLOT, AND A DEPRESSIBLE BUTTON CARRIED BY THE OTHER SLEEVE, THE BUTTON BEING SLIDABLE THROUGH THE ENTRY WHEN DEPRESSED AND BEING LOCKED FROM SLIDING THROUGH THE ENTRY WHEN NOT DEPRESSED, THE CONTACT TERMINALS INCLUDING A GROUND TERMINAL IN EACH SLEEVE, THE GROUND TERMINALS BEING LONGER THAN THE OTHER TERMINALS AND BEING SUFFICIENTLY LONG TO MAINTAIN ELECTRICAL CONTACT WITH ONE ANOTHER WHEN THE SLEEVES ARE SLID TO THEIR UNSEPARATED POSITION WITH THE ELECTRICAL CONTACT BETWEEN THE HOT TEMINALS BROKEN. 